Process for the preparation of halogenated benzoyl fluorides

Abstract

A process for the preparation of a halogenated benzoyl fluoride, which comprises contacting a halogenated benzotrifluoride of the formula ##STR1## in which m and n independently of one another represent an integer from 0 to 5, the sum of m and n being 5, with at least one sulphur compound of the formula ##STR2## in which X denotes fluorine, chlorine or hydroxyl and Y represents hydroxyl, or X and Y together denote an oxygen atom linked to the sulphur atom by a double bond, at an elevated temperature, and after reaction with the halogenated benzotrifluoride, removing the sulphur compound from the reaction mixture in the form of a compound of the formula ##STR3## in which X has the meaning given and Hal represents fluorine or chlorine, the reaction product is further reacted with potassium fluoride at an elevated temperature and under increased pressure.

What is claimed is: 
     
       1. A process for the preparation of a halogenated benzoyl fluoride, which comprises contacting a halogenated benzotrifluoride of the formula ##STR7## in which m and n independently of one another represent an integer from 0 to 5, the sum of m and n being 5, with at least one sulphur compound of the formula ##STR8## in which X denotes fluorine, chlorine or hydroxyl and Y represents hydroxyl, or   X and Y together denote an oxygen atom linked to the sulphur atom by a double bond, at an elevated temperature, and after reaction with the halogenated benzotrifluoride, removing the sulphur compound from the reaction mixture in the form of a compound of the formula ##STR9## in which X has the meaning given and   Hal represents fluorine or chlorine.   
     
     
       2. A process according to claim 1 wherein the reaction product is further reacted with potassium fluoride at an elevated temperature and under increased pressure. 
     
     
       3. A process according to claim 1 wherein chlorosulphonic acid is used as the sulphur compound. 
     
     
       4. A process according to claim 1 wherein a mixture of sulphuric acid and sulphur trioxide is used as the sulphur compound and, after the reaction with the halogenated benzotrifluoride, this mixture of sulphur compounds is converted with an acid halide of carbon, phosphorus or sulphur into a compound of the formula ##STR10## in which X and Hal have the meaning given in claim 1, and is removed as such from the reaction mixture. 
     
     
       5. A process according to claim 1 wherein pentachlorobenzotrifluoride is reacted with chlorosulphonic acid at 100° to 130° C. and the pentachlorobenzoyl fluoride formed is then further reacted with potassium fluoride in tetramethylene sulphone at elevated temperature and under increased pressure. 
     
     
       6. A process according to claim 1 wherein pentachlorobenzotrifluoride is reacted with a mixture of sulphuric acid and sulphuric trioxide, and, after reaction with thionyl chloride, the sulphuric acid and the oleum, as well as their reaction products, are removed from the reaction mixture by distillation, in the form of compounds of the formula ##STR11## in which X and Hal have the meaning given in claim 1. 
     
     
       7. A process according to claim 1 wherein the reaction is conducted at 70° to 150° C. 
     
     
       8. A process according to claim 2 wherein the reaction with potassium fluoride is conducted at 170° to 280° C. at 3-20 bars.